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3- L. HALL.

TELEPHONE TRUMPET. No. 350,737. Patented Oct. 12,1886.

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NITED STATES PATENT OFFICE.

EDXVARD L. HALL, OF BALTIMORE, MARYLAND, ASSIGNOR TO LOUIS NELKE, OFSAME PLACE.

. TELEPHONE-TRUMPET.

SPECIFICATION forming part of Letters Patent N0.350,737, dated October12, 1886.

Application filed March 3, 1886. Serial No. 193,882.

To all whom it may concern.-

Be it known that I, EDWARD L. HALL, a citizen of the United States,residing at Baltimore, in the State of Maryland, have invented certainnew and useful Improvements in Telephone-Trumpets, of which thefollowing is a specification.

My invention relates to a trumpet attachment fortelephone-transinitters, and is illustrated in the accompanyingdrawings, in which Figure l is a side view of an ordinarytransmitter-box with the trumpet attached. Fig. 2 is a side view of atransmitter-box and a section view of the trumpet. Fig. 3 is a front ormonth end view of the trumpet. Fig. 4 shows two views of the sound-wavedivider.

The letter A designates a straight tube or cylinder, B a flaring orbell-shaped mouthpiece attached to the straight tube, and O aring-shaped sound-wave divider secured in the straight tube. Thissound-wave divider has a peculiar shape, to wit: It is flaring ortapering in a direction opposite from the flare of the mouth-piece. Anaccurate description, perhaps, of the shape of this divider would be tostate that it is of thin metal, ring shape, and viewed sidewise has theshape of a frustum of a cone.

It will be understood from the foregoing that the largest diameter ofthe soundwave divider is nearest the small end d of the trumpet-the endwhich is placed against the front of the transmitter-box E. An annularspace, f, is left around the sound-wave divider and between it and thestraight tube A. This annular space constitutes one passageway for thesound-waves, and the central opening, g, through the divider constitutesanother. Practical test demonstrates that this particular constructionserves at once to concentrate and augment the voice-tones, and adaptsthe trumpet to work well with a Blake transmitter.

(No model.)

Two spring-wires, h, are each secured. ati to diametric opposite sidesof the straight tube, and the end of each passes through the side of thetube, and is attached to the soundwave divider C. From the point i wherethe wires are secured they project in opposite directions, and each hasan angle-bend, 7c, and an end, it. The two ends h act as clamp-arms totake on the top and bottom of the transmitter-box A, and thereby holdthe trumpet to its position. The two wires therefore have their innerends holding the soundwave divider, while their outer ends clamp thetransmitter-box.

Having described my invention, I claim and desire to secure by LettersPatent of the United States 1. A trumpet for attachment to telephonetransmitters, comprising a tube with a flaring mouth, and a sound-wavedivider having a central passageway, g, and secured in the tube, andforming an annular passage-way, f, as set forth.

2. A trumpet for attachment to telephonetransmitters, comprising a tubewith a flaring mouth, and a sound-wave divider having a ring shape andtapering like a i'rustum of a cone, and secured in the tube, as setforth.

3. A trumpet for attachment to telephonetransmitters, comprising a tubewith a flaring mouth, and a ring-shaped sound-wave divider forming anannular passage-way,f, and two attached wires whose inner ends passthrough the side of the tube and hold the said divider, while the outerends serve as a clamp to grasp the transmitter-box, as set forth.

In testimony whereof I affix my signature in the presence of twowitnesses.

EDWARD L. HALL.

Vitnesses:

J OHN E. MoRRis, J NO. T. MADDOX'.

